A mechanism known as an automated document feeder, or ADF, is a component found in photocopiers and scanners. It makes it possible to scan or copy multiple documents at once without the participation of the user. When digitizing a lengthy document for OCR input, an automatic document feeder, or ADF, is an extremely helpful instrument.

Large multifunction printers, scanners, and copy machines designed for workplace use typically include automatic document readers as one of their many features. The automatic document feeder (ADF) is typically included in even the smallest independent document printers. The mechanism that automatically feeds documents varies from model to model, but the vast majority of them can manage up to fifty printed sheets at once.

ADF scanners are not the same as flatbed scanners, which require the user to physically position each sheet on the scanning surface before scanning. Some large multifunction devices come equipped with both an automated document reader and a flatbed scanner. This gives users the ability to select the scanning mode that works best for the document they are scanning.